A sulfotransferase activity which catalyzes the transfer of sulfate group from 3´-phosphoadenosine-5´-phosphosulfate to galactosylceramide and triglucosyl monoalkylmonoacylglycerol has been demonstrated in antral and fundic mucosa of normal human stomach. With both types of mucosa maximum activity for sulfation of galactosylceramide was obtained at pH 6.8, whereas the pH optimum for sulfation of triglucosyl monoalkylmonoacylglycerol was 7.8. The reactions were stimulated by the addition of Triton X-100, Mg²⁺ and F^1-. The sulfotransferase activity of fundic mucosa for the synthesis of sulfated glyceroglucolipid was about two times higher than that of antral mucosa, while the enzyme activity for sulfation of glycosphingolipid was similar in both areas of the stomach.

The enzymatic activity which catalyzes the transfer of palmitic acid from palmitoyl coenzyme A to gastric mucus glycoprotein was demonstrated in antral and fundic mucosa of normal human stomach. Subcellular fractionation studies revealed that with both types of mucosa the enzyme activity was present in the microsomal fraction. The antral and fundic mucosa also exhibited similar enzyme activities, showed identical pH optimum, and required detergent, NaF and dithiothreitol. Optimum enzymatic activity for fatty acylation of mucus glycoprotein was obtained with 0.5% Triton X-100, 25 mM NaF, and 25 mM dithiothreitol at a pH of 7.4. The ¹⁴C-labeled product of the reaction comigrated on CsCl density gradient centrifugation with gastric mucus glycoprotein and contained the ester-bound palmitic acid.

The activity levels of sulfotransferase enzymes involved in the transfer of sulfate from 3’-phosphoadenosine 5’-phosphosulfate to mucosal membrane and mucus gel glycolipids were studied in fundic and antral mucosal biopsies of patients with severe and chronic gastritis, gastric atrophy, gastric ulcer, and gastric cancer. With sulfotransferase which catalyzes the sulfation of mucus triglucosyl glyceroglucolipid increase in enzyme activity over the control was observed in patients with chronic and severe gastritis, and gastric atrophy, while a decrease in activity was noted in patients with gastric ulcer and gastric cancer. The differences were significant at p < 0.001 for severe gastritis, gastric ulcer and gastric cancer. The increase in activity of sulfotransferase enzyme involved in the sulfation of membrane galactosylceramide over the control was observed in antral and fundic mucosa of all patients. Significant (p < 0.001) differences were found in patients with severe gastritis, gastric atrophy and gastric ulcer. The results indicate that considerable changes in the activities of the mucosal sulfotransferase enzymes involved in the synthesis of membrane and secretory sulfolipids occur in gastric disease.

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